In electrophotography, the fusing process for fixing toner on a recording medium may be conducted in many ways. The fusing process may be conducted utilizing radiant fuser members, such as infrared (IR) lamp heating members, to heat the toner and fuse the toner to a recording medium, such as paper, without contacting the recording medium with the heating member. Other fusing processes utilize hot roll fuser members, which typically comprise a metal core roll provided with various surface coatings. The metal core is heated typically with a lamp positioned inside of the core roll, and heat diffuses outward towards the surface of the fuser member.
Alternative fuser members may comprise belt fusers. A belt fuser typically comprises a polymeric belt with various coatings as the fusing member, wherein the belt is typically heated with a lamp or a ceramic heater, and the heat is transferred to the fusing belt by contact. These fusers typically have a faster warm up time from a cold start as compared with hot roll fuser members.
Furthermore, fusing may occur though induction heating. Induction heating fuser members typically comprise a substrate coated with a metal layer, and release or elastomeric layers. The metal layer is heated through an induction heating process. Induction fusing members may be comprised of a roll or a belt.
Joule heating has also been utilized in fusing processes in electrophotography. Joule heating occurs when an electrical current flows through a resistive material wherein the material's electrical resistivity to current flow generates heat. The Hwang U.S. Pat. No. 6,122,480 discloses a fuser member wherein the core of the fuser member is heated using Joule heating, and the heat diffuses outward from the core towards the surface of the fuser member.
The Ogasawara U.S. Pat. No. 5,907,348 and the Chen U.S. Pat. No. 6,393,247 disclose fuser members comprising a metal resistive layer, preferably nickel or aluminum, wherein Joule heating occurs in the metal resistive layer. The Chen U.S. Pat. No. 6,611,670 discloses an external Joule heating member to provide heat to a fuser member by contact.
As additional electrophotography devices of varying size, capability, and cost are developed, the need arises for improvements in components thereof, including fuser members.